* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
.container {
  width: 100vw;
  height: 100vh;
  position: relative;
}
#video {
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  height: 100%;
  background-color: black;
}
#btn {
  position: absolute;
  bottom: 50px;
  left: 50%;
  transform: translateX(-50%);
  width: 200px;
  height: 50px;
  border-radius: 25px;
  background-color: aliceblue;
  line-height: 50px;
  text-align: center;
}
